Current wireless communication systems do not adjust well to dynamic changes in the electromagnetic spectrum. As a result, these systems tend to provide a relatively low quality of service. As demand for high-bandwidth services increases, this problem will likely worsen.
Prior attempts to improve the ability of wireless communication systems to adjust to dynamic changes in the electromagnetic spectrum have focused on adaptation in a subset of dimensions available at a particular point in time. Data rates and processing gains have been modified to adapt specific waveforms, such as spread spectrum modulated signals, to a particular communication link condition. Various error-correction coding techniques with various parameters have been applied to a particular frequency assignment. Frequency adaptation techniques have been used in high frequency (HF) ranges. Frequency adaptation techniques have also been used in communication systems, such as wireless local area networks (WLANs), in which an open frequency is selected after a relatively slow seat for an open frequency.
Cellular communication systems typically operate at assigned channel frequencies. Slow assignments can use frequency division multiple access (FDMA) techniques. Adaptive modulation techniques have been investigated, but have been more or less limited to changing one or more parameters in a particular modulation scheme. Spectrum use can vary considerably throughout the world, which often necessitates a complex spectrum assignment process. Reallocation of bandwidth as a result of growth in commercial wireless markets could necessitate even more complex spectrum assignment processes in the future. In current wireless communication systems, one or more frequencies are statically assigned to a communication and sensor system (such as a radar system) without frequency overlap between the communication and sensor system and one or more other communication and sensor systems and with large spatial separation to prevent harmful interference between the communication and sensor system and one or more other communication and sensor systems.